Fuchisawa A, Lomas-Francis C, Hue-Roye K, Reid M E
Laboratory of Immunohematology, New York Blood Center, Long Island City, NY 10065, USA.
Immunohematology. 2009;25(1):18-9.
The Scianna blood group system comprises seven antigens encoded by alternative forms of SC. The SC gene also has two polymorphisms in the leader sequence, at nucleotides 54 (C/T, silent) and 76 (C/T, 26His/Tyr) in exon 2, which are not involved in expression of blood group antigens. The nucleotide change at position 76 has an NlaIII restriction enzyme site; thus, DNA samples from 100 Caucasians and 100 African Americans were analyzed for the SC nucleotide 76 change. DNA from Caucasian and African American donors was tested by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) using the restriction enzyme NlaIII. In selected samples, sequencing of exon 2 was performed. PCR-RFLP results for samples from 100 donors (mostly Caucasian) and 100 African American donors (400 alleles) showed the nucleotide 76T variant had a prevalence of 25 percent in Whites and 5 percent in African Americans. In 11 samples (2 C/C, 3 C/T, and 6 T/T) sequencing of exon 2 confirmed the presence of the expected nucleotides at position 76. The allele frequency in Caucasians was 0.75 for nt76C and 0.25 for nt76T. In African Americans, the frequencies were, respectively, 0.95 and 0.05.
斯恰纳血型系统由SC的替代形式编码的七种抗原组成。SC基因在外显子2的前导序列中也有两个多态性位点，分别位于核苷酸54（C/T，沉默突变）和76（C/T，26His/Tyr），它们不参与血型抗原的表达。第76位的核苷酸变化具有一个NlaIII限制性酶切位点；因此，对100名白种人和100名非裔美国人的DNA样本进行了SC核苷酸76变化的分析。使用限制性酶NlaIII通过聚合酶链反应（PCR）-限制性片段长度多态性（RFLP）对来自白种人和非裔美国人供体的DNA进行检测。在选定的样本中，对外显子2进行了测序。来自100名供体（大多数为白种人）和100名非裔美国人供体（400个等位基因）的样本的PCR-RFLP结果显示，核苷酸76T变体在白人中的流行率为25%，在非裔美国人中为5%。在11个样本（2个C/C、3个C/T和6个T/T）中，外显子2的测序证实了第76位存在预期的核苷酸。在白种人中，nt76C的等位基因频率为0.75，nt76T的等位基因频率为0.25。在非裔美国人中，频率分别为0.95和0.05。
